1. Field of the Invention
The present invention relates to an antiglare film that is provided on the surface of a window, a display, and the like. In particular, the present invention relates to an antiglare film that is provided on the surface of a display such as a liquid crystal display (LCD), a CRT display, an organic electroluminescence display (ELD), a plasma display (PDP), a surface electric field display (SED), and a field emission display (FED).
2. Description of the Related Art
In the field of displays such as liquid crystal displays, CRT displays, EL displays, and plasma displays, providing on the display surface an antiglare film having a concave-convex structure on the surface is known as means for preventing the degradation of visibility caused by reflection of external light on the display surface during viewing.
The following methods are known for producing such antiglare films:                a method of forming a concave-convex structure on an antiglare film surface by emboss processing;        a method of coating a coating liquid obtained by admixing particles to a binder matrix forming material and dispersing the particles in the binder matrix, thereby forming a concave-convex structure on an antiglare film surface.        
In an antiglare film having on the surface thereof a concave-convex structure formed by the above-described methods, the external light falling on the antiglare film is scattered by the concave-convex structure of the surface. As a result, the image of external light becomes smudgy and the degradation of visibility caused by the reflection of external light on the display surface can be prevented.
In the antiglare film in which convexities and concavities have been formed on the surface by emboss processing, surface convexities and concavities can be completely controlled. As a result, reproducibility is good. However, the problem is that where defects or foreign matter are present on the emboss roll, the defects spaced by a roll pitch appear on the film.
On the other hand, an antiglare film using a binder matrix and particles can be produced by using fewer operations than the antiglare film employing the emboss processing. As a result, the antiglare film can be manufactured at a low cost. Accordingly, antiglare films of a variety of forms in which particles are dispersed in a binder matrix are known (Japanese Patent Application Publication (JP-A-6-18706) No. 6-18706).
For example, the following methods for producing antiglare films using a binder matrix and particles have been disclosed:                a method using a binder matrix resin, spherical particles, and particles of irregular shape (JP-A-2003-260748);        a method using a binder matrix resin and particles of a plurality of different diameters (JP-A-2004-004777);        a method of using a film having surface convexities and concavities in which the cross-sectional area of convexities is specified (JP-A-2003-004903).        
The following methods have also been disclosed:                a method of using internal scattering in combination with external scattering and setting an internal haze of an antiglare film to 1-15% and a surface haze to 7-30% (JP-A-11-305010);        a method of using a binder resin and particles with a size of 0.5-5 μm and setting the difference in refractive index between the resin and the particles to 0.02-0.2 (JP-A-11-326608);        a method of using a binder resin and particles with a size of 1-5 μm and setting the difference in refractive index between the resin and the particles to 0.05-0.15, and a method in which the properties of the solvent used and the surface roughness are set within the predetermined ranges (JP-A-2000-338310);        a method of using a binder resin and a plurality of particles and setting the difference in refractive index between the resin and the particles to 0.03-0.2 (JP-A-2000-180611);        a method of setting a surface haze to 3 or more and setting the difference between a haze value in the normal direction and a haze value in the direction at ±60° to 4 or less with the object of reducing the variations in hue and the decrease in contrast occurring when the viewing angle changes (JP-A-11-160505).        
Thus, antiglare films of various configurations created to attain a variety of objects have been disclosed.
The properties of antiglare films used for the front surface of displays vary depending on the display type. In other words, the optimum antiglare film depends on the display resolution or object of use. Therefore, antiglare films of a large number of types are required according to the application object.
In displays for monitors of notebook personal computers and desktop personal computers, the user most often views the display screen for a long time from a front direction. Accordingly, antiglare films for use in monitors of notebook personal computers and desktop personal computers have to have the following properties: (1) high antiglare ability that makes it possible to smudge the image of external light falling on the display surface in the direction normal to the display screen, that is, in the front direction, and prevent the reflection of the external light image, and (2) absence of a white blurring phenomenon occurring when external light, in particular illumination such as from a fluorescent lamp, falls on the display surface. In addition, because the antiglare films are often used at work sites, the surface thereof is strongly required to have (3) high abrasive resistance. It is an object of the present invention to provide an antiglare film that combines: (1) high antiglare ability in the front direction; (2) absence of white blurring; and (3) high abrasive resistance.